Retention — how long things are kept. Files and records fall into classes, each with a standard period: transactional documents, 7 years; record attachments, 7 years; library files, 3 years; the audit trail, 7 years. Your company can set its own periods in System Setup → Document Management, under Retention settings (manage documents), and a single transaction type can carry its own period, overriding its class — one kind of paper kept longer than the rest. Your plan also carries standard periods, which apply until your company sets its own; the company's word wins. Expiry is eligibility, never an event: when a period runs out, the document becomes eligible to archive. Nothing is ever archived or deleted automatically.
Archiving. A finalized document can be archived from its own page's actions, and the library's Ready to archive list gathers everything that has become eligible, for the same decision in bulk. Archived is a state, not a disappearance: the document stays viewable, downloadable and exportable, still counts in statements and reports, and can be unarchived. It is how a tidy company marks its closed years without losing them.
Closing a period. A file-plan period folder can be closed in the library — one document type's year, or a whole year everywhere at once. Closing locks the folder's whole subtree: no uploads, no moves in or out, no deletes inside it; and it archives the finalized records whose files live there. Reopening lifts the lock — it never un-archives — and both actions are written to the activity trail with who, when, and how much was archived.
Legal hold. A document or a file can be placed under legal hold, with the reason recorded, by the people who may edit it. A hold beats everything: a held file cannot be purged, a held document's filed print is never replaced by a fresher render, and closing a period never weakens a hold inside it. Release is the same hands' work, and also recorded.
Trash. Deleting a file moves it to the library's Trash: its bytes are kept, it can be restored for 30 days, and after that window it is purged automatically; delete-forever is available sooner for anything not on hold (§14.7 — until the purge, trashed files still count toward storage). Deleting a file never harms the record it hangs on.
Year-end bundles. From Document Management (System Setup), build a year-end bundle for a financial year: one ZIP holding the rendered PDF of every finalized document in that year, each document's own attachments, and a manifest saying what is what, with checksums. The bundle is filed back into the library under a Year-end archives folder and downloads like any other file — one parcel, a whole year, ready for an auditor. It counts toward storage like any other file; it is a copy for keeping, not a move.
Exporting everything — the ZIP of every file you hold, with its manifest — is told at 15.7, because it matters most exactly when a subscription is in trouble.